The invention relates to improvements in building blocks which can be utilized as modules in construction work, for decorative or display purposes, in toy kits (such as erector sets) and for many other purposes. More particularly, the invention relates to improvements in building blocks which can be separably or permanently coupled with identical, similar or different building blocks to constitute skeleton frames of racks, roofs or other composite structures.
Supporting frameworks which form part of roofs, turrets, domes and like building structures are often assembled of prefabricated building blocks or modules which are coupled to each other to constitute a skeleton frame adapted to be employed to support laths, panels, planks, plates, sheets or other covering devices. The connections between the constituents of individual building blocks and/or between neighboring building blocks can include or constitute universal joints (such as spherical joints) or other types of junctions (e.g., those which employ discs). For example, a junction between two or more components of a building block can comprise a sphere which is made of a metallic material and whose surface is provided with a plurality of tapped bores or holes (e.g., with up to 18 bores or holes) for reception of rod-shaped components of building blocks. The end portions of the rod-shaped components are provided with external threads which are designed to mate with internal threads in the tapped bores or holes of the spherical junction.
Kits including building block components and junctions of the above outlined character enjoy a reasonable amount of popularity in certain fields, e.g., in certain branches of the construction industry wherein rapid assembly of different types of frames or like skeleton structures is of importance. However, such kits exhibit a number of drawbacks, especially as regards their versatility and reliability. For example, the mutual inclination of rods which are connected to a spherical junction cannot be changed so that a different junction must be employed whenever the required mutual inclination of two or more rods departs from a standard value. Furthermore, each of two or more different types of connections between those end portions of the rods which are remote from a spherical junction must be individually designed, constructed and assembled with attendant increase in the overall cost of a reasonably complex framework or the like. Special designs for connections between different sets of rods in one and the same skeleton frame or the like render the cost of such frames prohibitive for a number of applications, for example, in inexpensive erector kits or similar toy devices.
Another drawback of the aforedescribed skeleton frames which employ spherical junctions with tapped bores or holes and elongated rod-shaped components with externally threaded end portions is that the components can only transmit and/or take up relatively small torsional stresses. Moreover, if a skeleton frame employing one or more spherical junctions for externally threaded rod-shaped components is to be encased in a jacket or envelope consisting of panels, boards or the like, e.g., to constitute the roof of a building or a portion of a building, the components must be specially designed or they must be provided with specially designed attachments or adapters in order to be connectable with panels, planks, plates or like covering parts. This, too, contributes significantly to the complexity and cost of such skeleton structures.